The Creature Slaughterdome is a downloadable content "Circle of Slaughter" map for Borderlands 2.
- Access can be gained for players who do not own this DLC by accepting the mission chain Creature Slaughter with a player who owns it. Access is granted until the mission chain is completed.
http://borderlands.wikia.com/wiki/Add-on_content
Entering without it is still possible if a pre-order or paid owner's game is joined. If the mission is obtained but not completed this way, access is granted independently until mission completion.
http://borderlands.wikia.com/wiki/Natural_Selection_Annex
How do I accept the mission chain Creature Slaughter? If we try to travel to the DLC area, would I prevent them? Or do we travel normally and I pick up the mission chain upon entering?